Split the month's utility bills fairly between roommates. Share them equally, by the days each person actually lived there (perfect when someone moves in or out mid-cycle), by bedroom size or by any custom ratio, with flat-rate internet and trash optionally split evenly. Shares are rounded to the cent and always add up to the bill.
Last updated:
How to split
Split by
%
Kitchen, living room: % of room area split evenly
Bills for this period
$
$
$
$
$
$
Enter your values to see the result.
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How to use the Utility Bill Splitter
Choose how to split: equally, by days lived there, by room size or by custom shares.
List the roommates, one per line, with the number for that method, such as Jordan, 12 for 12 days.
Enter the bills for the billing period: electricity, gas, water, internet, trash and any other bill.
Decide on flat-rate services: tick the box to split internet and trash evenly no matter what.
Press Calculate split, then copy the summary or download the table to share with everyone.
Formulas used to split the bills
Equal: share = bill ÷ number of roommates
Days lived there: share = bill × your days ÷ total person-days
Room size: weight = your room area + (shared % × total room area ÷ number of roommates); share = bill × your weight ÷ total weight
Custom: share = bill × your share ÷ sum of all shares (shares can be percentages or ratios like 2 : 1)
Example (default inputs): $359.47 of bills for 30 days. Alex and Sam lived there all 30 days and Jordan 12, for 72 person-days. Electricity, gas and water ($264.47) are split 30 : 30 : 12, so Jordan pays $44.08 of them; internet and trash ($95) are split equally at $31.67 each. Alex pays $141.87, Sam $141.86 (one cent apart from rounding) and Jordan $75.74.
Which split method to use
Situation
Suggested method
Everyone lives there all month, similar use
Equally
Someone moved in or out, or was away for weeks
Days lived there
Rooms differ a lot in size; rent is split by size
Room size, with 20–40% shared space
A couple shares one room
Custom shares (2 for the couple, 1 for each single)
One person uses much more (space heater, home office)
Custom shares agreed in advance
Tips for stress-free shared bills
Agree on the method before the first bill arrives and write it into your roommate agreement.
Use the service dates printed on the bill, not the due date, when counting days.
Share a photo of each bill along with the split so everyone can check the totals.
Frequently asked questions
How do you split utilities when a roommate moves in mid-month?
Use person-days. Add up the days each person lived there during the billing period, then each person pays the bill times their days divided by the total person-days. If Alex and Sam were there all 30 days and Jordan moved in for the last 12, there are 72 person-days and Jordan pays 12/72, or one sixth, of the usage-based bills.
Should utilities be split by room size?
Room size works well for heating and cooling, because larger rooms cost more to keep comfortable, and it is often used when rent is also split by room size. Kitchens, bathrooms and living rooms are used by everyone, so this tool can treat a percentage of the space as shared and split that part equally.
Should internet be split by days or equally?
Internet and trash usually cost the same whether the house is full or not, so many households split them equally among the people living there that month and prorate only usage-based bills like electricity, gas and water. Tick the flat-rate box to do this.
What is the fairest way to split utility bills?
Equal splits are simplest and fair when everyone lives there full time with similar habits. Use days lived there when people move in or out or are away for long stretches, and custom shares when one room holds a couple or someone uses much more, such as running a space heater or working from home.
Why do the shares not divide evenly?
Some bills cannot be divided into whole cents, for example $100.00 among three people. The calculator gives each person their exact share rounded down, then hands out the leftover cents one at a time to the largest remainders, so the shares add up exactly to the bill.
Who should hold the utility accounts?
Usually one roommate holds each account and the others pay their share by a set date each month. Spreading accounts across roommates spreads both the credit checks and the responsibility, and keeping a shared record of each bill and payment prevents disputes when someone moves out.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.